STEM by ART: Teaching Science, Technology, Engineering, Math by ART Programming Arduino with Scratch (S4A) Fotios Gioulekas, Panagiotis Katsaros School of Informatics Aristotle University of Thessaloniki Greece http://stem.lupacovka.cz Computer programming & computer program . Computer programming: Calorie Calculator . act of writing computer programs to solve a problem . Computer program . structured collection of a sequence of instructions written using a Computer Programming Language to tell the computer to do a specific task Robotic arm playing https://www.calculator.net/calorie-calculator.html chess Image taken from: https://www.flickr.com/photos/steve_hoge/5143590110/ 1 Microcontrollers . A microcontroller is a computer system on a single chip that does a job (MCU, μC) . control electronic equipment . exists in electrical device, cars, washing machines, microwave ovens, telephones . includes central processing unit (CPU), memory (a small amount of RAM, program memory, or both), and programmable input/output peripherals, which are used to interact with various units Images taken from: http://d1gsvnjtkwr6dd.cloudfront.net/large/IC-ATMEGA168A-PU_LRG.jpg http://i.stack.imgur.com/whWVa.jpg http://slideplayer.com/slide/5881540/19/images/26/Fixed+Function+Integrated+Circuits+I+(Cont.).jpg 2 Arduino . Arduino is an open-source electronics prototyping platform that contains both hardware and software founded by Massimo Banzi and David Cuartielles in 2005 . open-source: Original design files are freely distributes enabling people to study them, make changes and share those changes with others . Electronics: Science sector dealing with the study of flow and control of electrons (electricity) and the study of their behavior and effects in devices using such electrons . Prototyping: An original model, form or an instance that serves as a basis for other things . Platform: A combination of a hardware system with software environment that can be programmed and execute other software Refs: https://www.arduino.cc/en/Guide/Introduction 3 Arduino Uno platform – I . One of the many flavors of Arduino platforms . It is able to read inputs (e.g. light on a sensor, a finger on a button, or a Twitter message) - and turn it into an output (e.g. activating a motor, turning on LEDs, publishing something online) . It can sense and react with the environment . The μC on the Arduino board is programmed using the Arduino programming language (Wiring Language which is based on C++) and the Arduino Integrated Development Environment (IDE) . The software consists of a standard programming language compiler and a boot loader that executes on the microcontroller Refs: https://www.arduino.cc/en/Guide/Introduction 4 Arduino Uno platform – II . Input voltage: 7-12 V (USB, DC plug, or Vin) . Max output current per pin: 40 mA Power Indicator 16MHz Clock Voltage regulator Image taken from: http://www.studentcompanion.co.za/wp-content/uploads/2015/12/Arduino-Uno-R3-pins.jpg 5 Arduino Uno Kit Shift Register Temperature sensor LDR 6 Putting parts together . How can I connect various sensors to Arduino? . How can I connect actuators to Arduino? . How can I tell or program an Arduino to do a job? 7 Programming Environment . It is an computer software framework that includes: . A text editor to create computer programs . A compiler to compile the created programs using the text editor into binary format or . An interpreter to execute the programs created directly 8 Scratch . Scratch is an open source visual programming language for teaching programming to children . One can create interactive stories, games, and animations – and share the creations with others on the we . Developed by the Lifelong Kindergarten group at the MIT Media Lab, USA . Programming resembles to putting parts together assembling a puzzle Source: https://scratch.mit.edu/ 9 Scratch for Arduino S4A - I . S4A, developed in 2010 by the Citilab Smalltalk Team, is a Scratch modification that allows for simple programming of the Arduino open source hardware platform . It provides a high level interface to Arduino programmers so as to manage sensors and actuators . An Arduino sketch (S4AFirmware16.ino) has to be loaded to the board to communicate with S4A through USB Source: http://s4a.cat/ 10 Scratch for Arduino S4A - II . Comparison of a simple program that blinks a LED connected to LED BUILTIN PIN # 13 on Arduino and in S4A LED # 13 Arduino Code S4A Program 11 Breadboards . A breadboard is used to create circuits and connect different sensors and actuators to the Arduino board through jumper wires, and electronic components . Horizontal hole groups are linked power and ground columns are connected vertically 12 Ohm's Law (Basic Electronics Law) . A physics law which states that current passing through a conductor is proportional to the input voltage . Voltage (V): is the measure of electrical potential . unit of measurement = Volts (V) . Current (I): is the amount of flow through a conductive material . unit of measurement = Amperes or Amps (A) . Resistance (R): is the material's opposition to the flow of electric current . unit of measurement = Ohms (Ω) Source: http://ohmlaw.com/ohms-law-for-kids/ 13 How a LED works . It is a light-emitting diode that emits light when activated based on the Electroluminescence (EL) . An optical phenomenon and electrical phenomenon in which a material emits light in response to the passage of an electric current . Electricity flows from a higher voltage to a lower voltage Long Short leg leg Source: https://en.wikipedia.org/wiki/Light-emitting_diode 14 S4A installation . Install S4A into your PC . Download the program from http://vps34736.ovh.net/S4A/S4A16.zip . Unzip it to a folder named S4A . Installing the Firmware into your Arduino . Download Arduino IDE from https://www.arduino.cc/download_handler.php and run the file arduino-1.8.5-windows.exe to setup it . Download S4A firmware from http://vps34736.ovh.net/S4A/S4AFirmware16.ino . Connect your Arduino board to a USB port in your computer . Open the firmware file (S4AFirmware16.ino) from the Arduino environment . In the Tools menu, select the board version and the serial port where the board is connected . Load the firmware into your board through File > Upload 15 Physical computing . Design interactive physical systems by the use of software and hardware that can sense and respond to the real world . smart automotive . traffic control systems . factory automation processes . Smart buildings . Robots Source: https://en.wikipedia.org/wiki/Physical_computing 16 Lab 1 – Control a LED from S4A (I) . Connect a LED and a 220Ω Resistor on the breadboard and with Arduino according to the schematic below _ Digital port #10 + GND 17 Lab 1 – Control a LED from S4A (II) . In S4A select . Digital off and on I/O . Drag and drop them to scripts area . Change them to Press here to switch on or off the LED #10 18 Lab 1 – Control a LED from S4A (III) . From control place wait 1 sec block in between the on of motion blocks . LED switches on and off every 1 sec if you click on the block of commands 19 Lab 1 – Control a LED from S4A (IV) . How to make Loops in the program? 20 Lab 1 – Control a LED from S4A (V) . When button is pushed, turn ON the LED for 10 seconds and then switch it OFF . 10KΩ pull down resistor is required to avoid inducing a dead short circuit when the button is pushed down Common pins Common pins Images sources: https://create.arduino.cc/projecthub/mjrobot/physical-computing-scratch-for-arduino-72661a , http://tymkrs.tumblr.com/post/19734219441/the-four-pin-switch-hooking-it-up 21 Lab 1 – Control a LED from S4A (VI) . Connect a LED and a 220Ω Resistor on the breadboard and with Arduino according to the schematic below _ Digital port OUT #10 220Ω 10KΩ 5V + GND GND Digital port IN #2 22 Lab 1 – Control a LED from S4A (VI) . S4A program 23 Lab 2 – Turn on a LED when LDR sensor is covered Automatic Night Light (I) .CdS - LDR (Cadmium Sulfide - Light Dependent Resistor) or photocell sensor .Its resistance is inversely dependent on the amount of light falling on it 5V Light Pin A0 0-5V 10KΩ 10kΩ resistor 220Ω resistor 24 Lab 2 – Turn on a LED when LDR sensor is covered Automatic Night Light (II) . Write down the Voltage values at Analog pin A0 CONDITION A0 VOLTAGE (mV) Lab’s light are switched ON Lab’s light are switched ON & Hand on the LDR Lab’s light are switched OFF Lab’s light are switched OFF & Hand on the LDR . What is the threshold value that differentiates darkness from lightness? 25 Lab 2 – Turn on a LED when LDR sensor is covered Automatic Night Light (II) . Program S4A . Sense the threshold voltage value of the sensor in an if loop . Depending on the value of the sensor . Switch on and off the LED 26 Lab 3 - Temperature Alarm – (I) . Program Arduino buzzer to buzz when temperature goes higher than a value +5V Temperature LM35 LM35 analog temperature sensor Voltage Supply: 4V – 20V Output Voltage Pin A3 10mv per Degree Ground Celsius 0-5V 27 Lab 3 - Temperature Alarm – (II) . Schematic Topology + GND 5V Digital Pin #11 GND Analog Pin A3 28 Lab 3 - Temperature Alarm – (III) . Read the voltage value in pin A1 . Does it correspond to real room temperature? . How to calculate the temperature value in oC since voltage values are read in A1 from the LM35 sensor? . Formula according to LM35 datasheet . Find what percentage of the range (1024 = 10bits representation of ADC) value in A1 is, multiplying that by the range itself (5000 mV), and divide it by 10 mV per oC . Temperature in oC = (A1 value * 500)/1023 Source: http://www.ti.com/lit/ds/symlink/lm35.pdf 29 Lab 3 - Temperature Alarm – (IV) .